贴面工艺对合成板材燃烧性能的影响

天然木材资源短缺,导致近年来合成板材使用量大大增加,为了了解不同贴面工艺对合成板材燃烧性能的影响。基于锥形量热仪法评定3种经过表面处理的合成板材（胶合板、中密度纤维板、刨花板）,探究表面处理技术对合成板材燃烧性能的影响。研究结果表明:贴薄木片与贴浸渍纸技术明显降低了胶合板的火灾危险性;贴薄木片技术明显降低了中密度板的火灾危险性;贴浸渍纸增加了刨花板与中密度板的火灾危险性。     

Calling,texting, and searching for information while riding a motorcycle: A study of university students in Vietnam

Objective: The objective of this study was to investigate the prevalence of calling, texting, and searching for information while riding a motorcycle among university students and the influences of sociodemographic characteristics, social norms, and risk perceptions on these behaviors.

Methods: Students at 2 university campuses in Hanoi and Ho Chi Minh City, the 2 largest cities in Vietnam, were invited to participate in an anonymous online survey. Data collection was conducted during March and May 2016.

Results: There were 741 respondents, of whom nearly 90% of students (665) were motorcycle riders. Overall prevalence of mobile phone use while riding is 80.9% (95% confidence interval [CI], 77.9–83.9%) with calling having a higher level of prevalence than texting or searching for information while riding: 74% (95% CI, 70.7–77.3%) vs. 51.7% (95% CI, 47.9–55.5%) and 49.9% (95% CI, 46.1–53.7%), respectively. Random parameter ordered probit modeling results indicate that mobile phone use while riding is associated with gender, motorcycle license duration, perceived crash risk, perceived risk of mobile phone snatching, and perceptions of friends' mobile phone use while riding.

Conclusions: Mobile phone use while riding a motorcycle is highly prevalent among university students. Educational programs should focus on the crash and economic risk of all types of mobile phone use while riding, including calling, texting, and searching for information. In addition, they should consider targeting the influence of social norms and peers on mobile phone use while riding.     

Causes of energy poverty in a cold and resource-rich country: evidence from Kazakhstan

Kazakhstan is an upper-middle-income country and one of the coldest countries in the world with rich energy resources and energy prices considerably lower than in developed countries. This paper presents the first comprehensive overview of household fuel use in Kazakhstan and assesses the causes and extent of energy poverty using the Households Living Conditions Survey dataset of 12,000 households. The results show that there is an overwhelming reliance on coal in Kazakhstan: 40% of all surveyed households use coal for heating, cooking and other needs. In general, liquefied petroleum gas is mainly used for cooking, coal and firewood for heating, while electricity is rarely used for heating. Energy poverty was less prevalent in oil and gas rich regions, due to low gas prices and higher income levels in those regions, while households located in the North Kazakhstan, Central and East Kazakhstan mainly suffer from lack of cleaner fuel options, income poverty, longer and colder winters and consequently energy affordability. Despite low energy prices in Kazakhstan, the results demonstrate that 28% of surveyed households spend more than 10% of their income on energy. Gas and district heating infrastructure coverage and income inequality across its regions contributed the most to energy poverty in Kazakhstan. Energy prices are regulated and indirectly subsidised. Removing energy subsidies alone may worsen energy affordability of households. Offering direct subsidies to cover part of the energy expenditures may not fully solve the problem, but subsidies, interventions for efficient technologies and fuels, dwelling energy-efficiency improvements are necessary.     

Do we have to incorporate ecological interactions in the sensitivity assessment of ecosystems? An examination of a theoretical assumption underlying species sensitivity distribution models

Species sensitivity distributions (SSDs) are statistical distributions which extrapolate single-species toxicity test results to ecosystem effects. This SSD approach assumes that ecological interactions between populations, such as grazing and competition, do not influence the sensitivity of ecosystems. The validity of this assumption in a simple freshwater pelagic ecosystem was tested using ecosystem modelling. For each of a 1000 hypothetical toxicants, a lognormal SSD was fitted to chronic single-species EC10s of the species present. As such, these distributions did not account for ecological interactions and were therefore termed 'conventional SSDs' (cSSDs). Next, sensitivity distributions that did take into account ecological interactions were constructed (eco-SSD) for the same 1000 toxicants, using an ecosystem model. For 254 of the 1000 hypothetical toxicants, mean and/or variance of the cSSD were significantly higher than mean and/or variance of the eco-SSD, as such rejecting the general validity of the tested assumption. A classification tree approach indicated that especially toxicants which directly affect phytoplankton (i.e. herbicides) may have a higher mean for cSSD than for eco-SSD. Conversely, means of eco-SSD and cSSD tend to be equal for toxicants directly affecting zooplankton and fish, e.g. insecticides. For the 254 hypothetical toxicants for which the tested assumption was false, a predicted no effect concentration (PNEC) calculated as the lowest single-species EC10 divided by an application factor of 10 was on average a factor 10 lower than the corresponding ecosystem-NOEC calculated by the ecosystem model.     

Mutagenic properties of PM2.5 air pollution in the Padana Plain (Italy) before and in the course of XX Winter Olympic Games of "Torino 2006"

PM2.5 is one of the most important aspects of environmental health. This air pollutant is breathable and it is implicated in several chronic adverse health effects such as the decrease of respiratory functionality and cancer. Several in vitro bioassays are able to predict the mutagenic/carcinogenic activity of the environmental pollutants and mixtures of them. In this study PM2.5 air pollution was daily monitored in three cities located in the Northern part of Italy and the mutagenic properties of the PM2.5 organic extracts were also assessed. Samplings lasted 14 months and cover the period of the Winter Olympic Games of "Torino 2006". In this work, the levels of PM2.5, its mutagenic properties (detected with Salmonella typhimurium assay), the role of the Olympic Games as environmental factor and some meteorological data are discussed. The mean concentration of PM2.5 measured in Torino was 45.4 (+/-30.6) microg/m(3), in Pavia 37.6 (+/-25.6) microg/m(3), in Verona 43.1 (+/-28.5) microg/m(3). Findings of the monthly pool bioassay were in Torino 107 (+/-104) net revertans/m(3), in Pavia 108 (+/-89) net revertans/m(3), in Verona 128 (+/-109) net revertans/m(3). The Olympic Games period data show that PM2.5 pollution and its load of mutagenic potential are different and partially independent phenomena. The Olympic Games had not a great impact on the PM2.5 pollution. The exclusive PM2.5 gravimetric analysis shows a potential human risk if compared with the latest international guide values but it does not describe exhaustively the human health risk associated to the presence of this particular air pollutant. Moreover, the chemical and biological activity qualification of the PM organic extracts as a whole, can instead improve the knowledge.     

Immediate biomarker responses to benzo[a]pyrene in polluted and unpolluted populations of the blue mussel (Mytilus edulis L.) at high-latitudes

Immediate biomarker responses of two high-latitude populations of the blue mussel Mytilus edulis to benzo[a]pyrene (B[a]P) were evaluated. Mussels collected from a clean and a polluted site in southwest Iceland were exposed to the nominal dose of 100 microg B[a]P L(-l) for 3 h, after 4 days of acclimatization in clean seawater. To test the sensitivity to the toxicant and immediate biological responses, the following biomarkers were used: DNA single strand breaks, heart rate and feeding rate. All the biomarkers revealed differences between the study sites. Irrespective of the origin of the organisms, the short time exposure to the high B[a]P concentration did not induce DNA single strand breaks or significantly affect the feeding rate. However, the heart rate results showed significantly different responses. The mussels from the polluted site (Reykjavík harbour) increased their heart rate when exposed to B[a]P, while no difference was observed between the heart rate values of the individuals from the clean site (Hvassahraun). The mussels seem to sense the pollutant they have been previously exposed to, and their acute response indicates physiological adaptation to the polluted environment. The results indicate limited sensitivity and temporal predictivity, i.e. transient measurable changes of these biomarkers, as well as showing that the background of the organisms should be considered when evaluating short-term biomarker responses to contaminants.     

Oxygen bioavailability and haemoglobins in the brine shrimp Artemia franciscana

Bioavailability of oxygen for the saline-water invertebrate Artemia franciscana was studied, since both oxygen concentration and oxygen diffusion rate change with salinity. Total haemoglobin concentration and the relative contribution of each of three haemoglobins was measured in specimens acclimated to different salinities and oxygen concentrations. Both haemoglobin concentration and contribution were influenced by salinity and the group observed (males, females with and females without eggs). Multiple regression analysis showed that total haemoglobin concentration was better correlated with oxygen concentration than oxygen partial pressure. The relative proportions of haemoglobins 1, 2 and 3 were better correlated with oxygen partial pressure than oxygen concentration. These results are related to the oxygen carrying capacity and oxygen affinity of the haemolymph. Our results show that oxygen bioavailability in a saline-water environment depends on the response (relative contribution of Hb1, Hb2 and Hb3 or total haemoglobin concentration) that is studied. They also show that oxygen concentration and oxygen partial pressure have a different physiological impact on brine shrimp.     

Isolated bacteriocyte cell suspensions from the hydrothermal-vent tubeworm Riftia pachyptila,a potent tool for cellular physiology in a chemoautotrophic symbiosis

The hydrothermal-vent tubeworm Riftia pachyptila relies entirely on its intracellular chemoautotrophic symbionts to sustain its metabolism. The host must therefore provide them with inorganic metabolites, including carbon. This study describes a tool for studying cell processes occurring in a bacteria-containing cell by the dissociation of trophosome cell types. The physiological assays performed on cell preparations focused on carbon dioxide conversion and transport processes. Trophosome tissue was mechanically dissociated, resulting in cell suspensions enriched in small (7-20 µm) bacteriocytes, which were viable for several hours. In addition, medium-term cell cultures were also attempted. As a start to the understanding of the CO₂ metabolism of these cells, we were interested in evidence of carbonic anhydrase (CA) isoforms, ATPases and chloride exchangers. Variations in intracellular and extracellular pH, and in intracellular concentrations of sodium, potassium and chloride, were followed after addition of selective inhibitors. The data presented here suggest the occurrence of potential cytosolic and membrane-associated carbonic anhydrase isoforms in the bacteriocytes, proton-driven sodium-ATPases and a well represented anion transporter exchanging intracellular chloride against extracellular anions.     

Predicting the economic impact of an invasive species on an ecosystem service.

Quantifying the impact of alien invasive species on ecosystem services is an essential step in developing effective practices and policy for invasive species management. Here we develop a stochastic bioeconomic model that enables the economic impact of an invasive pest to be estimated before its arrival, based on relatively poorly specified ecological and economic parameters. We developed the model by using a hypothetical invasion of the varroa bee mite (Varroa destructor) into Australia and the negative flow-on effects that it would have on pollination by reducing honey bee populations, giving rise to a loss of pollination services, reduced crop yields, and additional production costs. If the mite were to continue to be prevented from entering the country over the next 30 years, we estimate that the economic costs avoided would be U.S. $16.4-38.8 million (Aus $21.3-50.5 million) per year. We suggest that current invasion response funding arrangements in Australia, which do not acknowledge these avoided damages, require amendment.     

Degradation of carbendazim by UV/H<Subscript>2</Subscript>O<Subscript>2</Subscript> investigated by kinetic modelling

The transformation of the fungicide carbendazim (methyl-2 benzimidazole carbamate) induced by hydroxyl radical generated by the UV photolysis of H₂O₂ has been studied in dilute aqueous solution. The efficient reaction of hydroxyl radicals with carbendazim led to the rapid degradation of carbendazim. The study of reaction kinetics yielded a second order rate constant of 2.2±0.3 10⁹ M⁻¹ s⁻¹ for HO^· radicals with carbendazim. This value is in agreement with a high reactivity of HO^· radicals with carbendazim. Most degradation products were identified by high performance liquid chromatography mass spectrometry (HPLC-MS). In the presence of hydrogenocarbonate and carbonate ions, hydroxyl radicals were quenched and in turn carbonate radicals CO₃ ^·− were formed. Carbonate radicals are indeed known to react efficiently with compounds containing electron-rich sites such as nitrogen or sulfur atoms. The use of a kinetic modelling software gave evidence for the occurrence of such reactions with carbendazim. The second order rate constant of carbonate radical with carbendazim was equal to 6±2 10⁶ M⁻¹ s⁻¹. Electronic Publication